Method of clamping steel core aluminum stranded wires

ABSTRACT

A method of clamping steel core aluminum stranded wires by inserting a steel core wire into a steel core wire inserting hole in a steel sleeve provided with a plurality of axial slits on the outer wall of the steel core wire inserting hole and having a through screw hole directed to the axis near the base of the slits, screwing a push screw to be screwed into the above mentioned screw hole to press the steel core wire with the tip so that the head of the screw may be hidden in the screw hole, inserting this steel sleeve into a cylindrical part of an aluminum sleeve into which it can be inserted with a slight clearance and compressing the aluminum sleeve on the outer periphery.

United States Patent 1 Noda 1 1 METHOD OF CLAMPING STEEL CORE ALUMINUMSTRANDED WIRES [75] Inventor: HiroshiNoda,Shinagawa-ku,Tokyo,

Japan [73] Assignee: Sanwa Tetsuki Kougiyou Kabushiki Kaisha, Tokyo,Japan [22] Filed: Oct. 5, 1971 [21] Appl. No.: 186,719

[52] US. Cl 29/459, 29/517, 29/526,

24/125 N, 287/79, 287/109, 24/115 A 51 Int. Cl 1323p 3/00, B23p 25/00[58] Field of Search 29/516, 517, 458,

29/459, 526; 24/115 A, 123 W, 125 NX, 135 N; 287/79 X, 78, 76, 109 XNov. 6, 1973 Primary Examiner-Charlie T. Moon Attorney-Holman & Stern[57] ABSTRACT A method of clamping steel core aluminum stranded wires byinserting a steel core wire into a steel core wire inserting hole in asteel sleeve provided with a plurality of axial slits on the outer wallof the steel core wire inserting hole and having a through screw holedirected to the axis near the base of the slits, screwing a push screwto be screwed into the above mentioned screw hole to press the steelcore wire with the tip so that the head of the screw may be hidden inthe screw hole, inserting this steel sleeve into a cylindrical part ofan aluminum sleeve into which it can be inserted with a slight clearanceand compressing the aluminum sleeve on the outer periphery.

3 Claims, 4 Drawing Figures PATENIEDRBV s 1915 3.769.685

v INVENTOR- l/l roshi Noll METHOD OF CLAMPING STEEL CORE ALUMINUMSTRANDED WIRES BACKGROUND OF THE INVENTION There is known such method ofclamping steel core aluminum stranded wires as with an anchor clamp or astraight sleeve. The present invention relates to improvements in suchmethod.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. (1) is a side view in partialsection of this method as used in an anchor clamp.

FIGS. (2) and (3) are cross-sectional end views on line 1-1 2--2 in FIG.(1) respectively before and after the compression.

FIG. (4) is side view of this method as used in a straight sleeve.

DESCRIPTION OF PREFERRED EMBODIMENTS First of all, the case of an anchorclamp shall be explained with reference to the drawings. According tothe present invention, in a steel sleeve (1) having a hole for insertinga steel core wire (w) of a steel core aluminum stranded wire (W), aplurality of axial slits (la) are made on the outer wall of theinserting hole, a through screw hole radial to the axis of the hall ismade near the base of the slits and a push screw (2) is screwed into thethrough screw hole. The steel core aluminum stranded wire to be clampedhas the aluminum core part on the outer periphery at the end partscraped off and has the steel core wire (w) inserted into the insertinghole of this steel sleeve to the bottom thereof. This inserting hole iscoated in advance with a compound mixed with abrasive particles, such ascarborundum, so that the frictional force of the inserted steel corewire may be increased. Then the push screw (2) is strongly screwed so asto bite at the tip into the steel core wire. For this purpose, asrequired, there may be used a push screw which has its head exposed outof the steel sleeve even after it is screwed in, as shown in the drawingand is then strongly screwed to have the head twisted off. The pushscrew is so made as to be hidden in the screw hole after it iscompletely screwed in. Then this steel sleeve is inserted into acylindrical hole of an aluminum sleeve (3)., This hole is so designed asto leave only a slight clearance between it and the steel sleeve. Afterthe insertion, the aluminum sleeve is compressed having the outerperiphery from the end on the push screw to the other end so that thethree members, of the aluminum sleeve, the steel sleeve and the steelcore aluminum stranded wire may be integral. Since the push screw (2)bites into the tip of the steel core wire, there is no fear that whenthe aluminum sleeve is compressed the steel core wire will come out. Thesteel sleeve, provided because of a flexibility with the slits, willstrongly grip the steel core wire due to this compression. That is tosay, with only one compression,

ing portion.

the above mentioned three members can be made strongly integral.

Conventional steel sleeves are not provided with the above mentionedslits (la). Such steel sleeves are compressed to grip the steel corewire after it is inserted into the sleeve. By this compression, thesteel sleeve will be bent and a bend correcting step will be required.During such a step, the reduction of the gripping force for the steelsleeve is unavoidable. Even if such bend is corrected, in order that thesteel sleeve may be reasonably inserted into the aluminum sleeve, itwill be necessary to provide a proper clearance between them. It isconsidered necessary to insert a collar for filling the clearance or towind a wire on the outer periphery of the steel sleeve before thealuminum sleeve is compressed.

On the other hand, in the present invention, no steel sleeve compressingstep is necessary. The steel sleeve has no space for generating bends.When the steel sleeve is inserted into the aluminum sleeve and thealuminum sleeve is compressed, the three members can be made stronglyintegral as mentioned above. It is a feature of the present inventionthat the problem of compressing the steel sleeve and the disadvantageaccompanying it are eliminated as in the above.

In the above, an anchor clamp has been described as an example. However,the present invention can be utilized also in a straight sleeve (5) asin FIG. (4) in exactly the same manner. It is only different that, in astrain clamp, the electric wire (W) is inserted only in one direction,whereas, in a straight sleeve, the steel core wires (w) are inserted asopposed to each other on both sides of the steel sleeve (4).

What is claimed is:

l. A method of clamping steel core aluminum stranded wires by insertinga steel core wire into a steel core wire inserting hole in a steelsleeve provided with a plurality of axial slits on the outer wall of thesteel sleeve defining the core wire inserting hole and having a throughscrew hole directed toward the axis near the base of the slits; screwinga push screw into said screw hole to press the steel core wire at itstip; then inserting said steel sleeve into a cylindrical hole in analuminum sleeve into which it can be inserted with a slight clearance;and compressing the aluminum sleeve at the outer periphery.

2. The method as claimed in claim 1 including the further steps ofscrewing said push screw in as far as it will go and if the head isprotruding from the contour of the steel sleeve, then removing at leastthat protrud- 3. The method as claimed in claim 1 including the furtherstep of coating the steel core wire inserting hole with abrasiveparticles before inserting the steel core wire into said hole.

1. A method of clamping steel core aluminum stranded wires by insertinga steel core wire into a steel core wire inserting hole in a steelsleeve provided with a plurality of axial slits on the outer wall of thesteel sleeve defining the core wire inserting hole and having a throughscrew hole directed toward the axis near the base of the slits; screwinga push screw into said screw hole to press the steel core wire at itstip; then inserting said steel sleeve into a cylindrical hole in analuminum sleeve into which it can be inserted with a slight clearance;and compressing the aluminum sleeve at the outer periphery.
 2. Themethod as claimed in claim 1 including the further steps of screwingsaid push screw in as far as it will go and if the head is protrudingfrom the contour of the steel sleeve, then removing at least thatprotruding portion.
 3. The method as claimed in claim 1 including thefurther step of coating the steel core wire inserting hole with abrasiveparticles before inserting the steel core wire into said hole.